(Changes city in dateline to Santiago, adds context, Codelco statement and statement from striking unions)

SANTIAGO, June 22 (Reuters) – Labor unions at Chile’s Chuquicamata copper mine voted on Saturday to reject the latest contract offer of government-controlled mining company Codelco, and to continue the week-long strike at the sprawling production site.

The unions went on strike eight days earlier after initial negotiations over a new collective labor contract failed.

“With this result, the strike continues,” the unions said in a statement after the Saturday night vote.

Codelco delivered its most recent proposal on Tuesday after clashes at the mine that led to police firing rubber bullets and tear gas as striking workers tried to block access to a site.

The contract offer maintained previous benefits, including a bonus and loan options of as much as $20,000 per worker while strengthening parts of the worker’s retirement plan. Unions said the new retirement perks were not enough, and that the offer did not meet their demands for better healthcare coverage.

“We are not going to settle for crumbs,” Hector Milla, president of one of the three striking unions, told reporters after the vote.

Codelco has five days to make a new offer. But the company issued a post-vote statement saying last week’s proposal was its “final offer,” and “represented the best effort that management can make within the framework of collective bargaining.”

Chuquicamata, or “Chuqui,” one of Codelco’s key copper deposits, faces a challenge to maintain output as the open-pit mine undergoes a complex $5 billion-plus transformation into an underground shaft mine. The overhaul has meant job cuts in some areas of the mine, making relations tense with workers.